Bush's so-called faith-based initiative green-lighted taxpayer dollars to local churches and other religious organizations to help them expand their social services in local communities. It's an arrangement President Obama supports as well.

But amid persistent criticism that the initiative walks a fine constitutional line, the administration moved to "strengthen the constitutional and legal footing" of the policy Wednesday with an executive order to add safeguards against inappropriate entanglement between church and state.

Religious organizations that receive federal grants are already prohibited from using the money directly for religious activities and cannot discriminate on the basis of religion when providing their services.

Now, however, individuals seeking aid through federal programs who might be put off by the religious nature of an organization will receive greater deference. Agencies must identify alternative service providers to those who object.

The executive order also enhances transparency of the program, requiring government agencies to post online a list of faith-based groups receiving taxpayer funds and "to monitor and enforce standards regarding the relationship between religion and government in ways that avoid excessive entanglement."

Groups are reminded they must keep their religious activities entirely separate in time and location, from the services provided with federal funds. But they are not required to remove religious signs and symbols from their facilities or religious references from their names.

"These are important, substantive changes that are directly responsive to the recommendations of church-state experts across the ideological spectrum," said Joshua DuBois, executive director of the White House Office of Faith-Based and Neighborhood Partnerships.

But critics of the policy say Obama's executive order did not go far enough to ease concerns about preferential treatment for religious groups, or fulfill his campaign promise of ending federal funding for groups who discriminate in their hiring.

Faith-Based Order Silent on Employment Discrimination

"I'm disappointed," said the Rev. Barry W. Lynn, executive director of Americans United for Separation of Church and State. "I am particularly frustrated that President Obama still has done nothing to ban hiring bias by publicly funded religious charities. That's the 800-pound gorilla in the room. No American should be denied a government-funded job because he or she holds the 'wrong' views about religion."

Rev. Harry Knox of the Human Rights Campaign, a gay and lesbian rights group, who is also a former member of Obama's faith-based and community initiatives advisory council, praised the executive order as a step forward but called its failure to implement employment non-discrimination protections troubling.

"Until this administration makes clear that religious groups cannot circumvent federal, state and local anti-discrimination protections to discriminate against LGBT employees, the faith-based initiative will remain a deeply flawed program," Knox said.

Faith-based organizations received more than $2.1 billion in federal social service grants in 2005, according to the most recent data published by the Government Accountability Office.